Document 82j8qr50rBO8rwp9bxGbQjrpB

OwWwHuTEmflUSk3,5w"aSSS) T APR 1978 Experimental Polychlorinated Biphenyl Toxicosis in Germfree Pigs 0. P. Miniats, N. S. Platonow and H. D. Geissinger* ABSTRACT The effects of polychlorinated biphenyls were studied in eight germfree pigs. Begin' ning at fourteen days of age, two pigs each were fed daily 12.5, 25, 50 and 100 mg/kg body weight of polychlorinated biphenyls as Aroctor 1254. Three germfree pigs were negetivenwntrola. Clinically the treated pigs had ineppetance, a hemorrhagic diarrhea, erythema of the nose and the anus, retarded growth, distended abdomen and at the higher dose levels, ineoordlnatlon and coma followed by death. Deaths occurred in 11 to 35 days after exposure. At necropsy, the piglets exhibited grossly enlarged mottled liver, erosions of the gas tric mucosa, hemorrhages through the me* sentery and the intestinal wall, a fibrinous pericarditis, a hypoplastic thymus and con gested swollen thyroid glands. The histopa thological lesions included hepatic centrolobular necrosis, interstitial myocarditis, en docarditis, myopathy of the muscles, gastric erosions and colitis. All of the organs ex amined for polychlorinated biphenyls had elevated residue levels which were parti cularly high In the fat, liver, psoas muscle, brain and kidney and were higher than has been reported in conventional pigs fed ap proximately equal concentrations of polychlori nated biphenyls. The severity of clinical signs, pathological changes and tissue concentrations wsro di rectly related to the does administered and were more pronounced in the germfree piga than has been described In conventional pigs. 'Dceerlmcnt tl Clinical Sladln (Mlnlala) and Departm*t ,1 Blachcmical Stiintu (PUtomv and GctoIncarl. Ontarta Veterinary Callert, UnlreraU? ef Guelph, Guelph. Ontario. Canada. N. Platonov la praoeatlr at Labasr Canada. Ball. QaaUe. Canada. Araclar la a rastatorad trademark ef the Memento Ca. Tha aroclara era canaht nUturaa < palrchtarinatod fctohsarle and era daecrlhad hr a (mi Stall number. Tha tint tv* dlfita Indicate that tha matorlala an pelrchlerinetod biphenyls and tha laat tva dlrlto Indicate tha narcant chlorine content in tha misters, a.g. Amlor 1114 to a selrchkrlneted blphenrto 14% chlorine content. Subwtttad April 1*. IW. These differences appear to be related to the absence of e microbial flora in the germfree intestine and/or to lesser developed detoxi fying enxyme systems in the liver of the younger pig. RftSUMfi Lee auteurs ont itudii I'effet dee diphinylee poiychloria, chea huit porcelete axiniques. Die I'lge de 14 Jours, quatre groups* de deux porcelete returent reapectivement 12.5, 25, 50 et 100 mg de diphinyles poiychloria par kilogramme de poids vif, sou* la form* d'Aroclor 1254. Trois autres porceleta exinlquea serrirent d* timoln*. Let porcelete expiri* mentaux manlfestirent de I'inappiUnce, one diarrhie himorrsgique, de I'irythim* nesal et anal, un retard de croissance et une dis tension abdominal*; ctux qui avaient re;u la plus forte dose d'Arodor 1254 manifeetirent en plus de ('incoordination, du coma et finirent par mourir. Lee mortality* survinrent entre le He et le 85* jour do I'expirlenee. La nicropsie de cee porceleta ririla Ise litions macroscopiques sulvant**: hypertrophie et aspeet nodulaire du foie, irotions d* la muqueuae stomacale, himerraglee du mieentire et de la parol intestinal*, piricardtt* fibrlneuse, hypoplasia du thymus, hyperiml* et hypertrophie dee thyroids*. Lee listens hletologiqoes Incluaient de la niereee hipatiqu* centro-lobulaire, do la myoeardite in* teratitielle, de Tendocardite, de la myepathie, dee iroslona gaatrlquea et d* la collte. La recherche dt l'Arocter 1254 dana divert orga ns* en rivila une quantlti ilavie, partlculiirement dans le tlssu edlpeux, I* foie, lee psoas, Is cervoau at lea reins. Cette quantlti e'avira aupirieure 4 cell* qn'on svait di}4 retrouvie dans lea organte dea pores eon* ventionnels auxquels on avalt donni dea con centrations iquivalentes d'Arodor 1254. La gravtti des aignes cllnlquet, dos liaions maeroecoplquee et hletologlques, alnsi qne la quantlti de risldu tiasulalre, as rivilirent dlrectement proportionnelles i la doe* d'Aroder 1254 et pine marquies ches lee porcelete 192 Can. J. comp. Mod. HONS 000850 for WEE virus, eastern equine encephalitis virus was transmitted experimentally via the oral route in a herbivorous species, the snowshoe hare (31). In nature, cannibalism among squirrels is observed frequently along prairie highways due to roadkiils during the summer. Therefore, it is possi ble that oral exposure of squirrels to high titres of WEE virus would occur upon the ingestion of infected squirrel carcasses. Recovery of WEE virus from renal tissue and the occasional recovery from urine indicated WEE virus could be excreted via the urinary tract. Arbovirus viruria had been reported previously in clinical human cases (26). In view of the viruria and the susceptibility to intranasal exposure it is possible that WEE virus could be trans mitted via an excretory-inhalation pathway from animal to animal. However, the sur vival of the virus in voided squirrel urine would be questionable because of the sensi tivity of WEE virus to fluctuations in temperature and pH (18). REFERENCES 1. ALBRECHT, P, Llpotroplem of th* virua of th# d.i ti te-ii, teas. t. ALBRBCHT, P. Pethogenaale of experimental infoc* (ion with tleb-bom# encepbulliU vlni*. In Biology of Virua** of th* Tick-born* Eneophelitle Complex, pp. 247.2(7. H. Llblkova, Editor. Now York: Aeadamlo Prtoi. IMt, I. ALBRBCHT. P.. M. MRBNOVA on4 B. KARBLOVA. Paraffin smbaddlng taebnlquaa for Iramunofluoreaeont demonstration of nourotrople vtruaoo. AeU. vlrol. IOi IR6.160. ISIS. 4. RANG. P. B. ond C. N. LUTTRBLL. factor* in pathogen**!* of virua dlMOMi, Adv. virus Rot. Si 199-144. llll. I. BROWN, L. N. and R. A. PARKER. Somo factor* affecting ploqu* i!m of WBB vlruo, Am. J. vot Boo. lit 487-498. 1114. I. BURNET, P. M. lnepparent (eubeNnieal) Infection of tho rot with louplng-ill rims. J. Path. Boot. 411 in Ba#kateh#w*n bird* and mammal* 19I8-190*. Can. 4. Mieroblol. Iti 111-141. 1*11. I. CORBI8TAN, B. C., L. C. LaMOTTB and D. G. SMITH. Susceptibility of bat* bo eortain encephallUl virtu. Proe, Podn Am. Soo, *xp. Biol. Hi SB4. IH(, I. DANES. L.( V. RYCHTBROVA, V. RLtMRNT and 4. HRUSKOVa. Ponotratlon or Vonwuolan oqulnt 0. PR1IDBMANN, U. Pormoabilltr of blood-brain bar rior to nourotrople viniM*. Areb* Path. SI i 111. III. 1041, 1. FROBBCHLB. J. K. Propagation of wwUrit equine encephalitis v(ru* in mleo following Intrnmueculer ??i 88*1*884*' Proe- Soo. oxp. Biol. Mod. * * ' C- B. PBOBRSON and 4. L STOOKBY. A comparison of tbo tiaiuo ImioP* produced In adult hamsters by two (train* of avirulent Venetulaan equine eneephalomyelltb virua. Am, J. Path. II: 11-24. 1171. I. GWATKtN. R. On tho *ueoptibiHty of ground auirreli to virus of eoulno tncapbelomyeiiu* and t1i1c1k-*118a.* 1p18o9e.tlble vector*. Can. J. eomp. lied 1, I. HAYLES, L. B. Susceptibility of tb* Mongolian gerbit* (Merlon** ungulculeiae) to western equine encephaliil*. Can. 4. Mieroblol. IS i 941-944. 1*7* i. HRUSKOVA, 4., L. DANES, A. 4BLINKOVA. J. KRUML and V. RYCHTBROVA. Subeutaneoui and inhalation infection of guinea pig* with Vnetulan equine encephalomyelitis virua, Acta vlrol. )|t 41*. 421- 1961. 1. JOHNSON. R. T. and C. A. MIMS. Pathogenoel* of viral infection! of the nsrvoue intern. New Engl. J. Mod. ITI: 88-10. 84-92. 1918. f. LaMOTTB. L. C. JR. Japanese B encephalitis In bat* during afmulatod hibernation. Am. 4. Hyg, ITi 101-108. 1968. 1. LENNETTB. E. H. and N. R. SCHMIDT. Diagnos tic Procedure* for Viral and Rlckutulal Infection*. 4th Bd. pp. 1-66. American Public Health An. Ine. 1969. > LEUNG. M. K A. BURTON. J. IVBRBBN and J. MeLINfOCK. Natural Infection* of Rlebardeon'a ground aqulrreie with wcatorn equina oneephalomvolltia virua, 8aakatebwn. 1964-1971. Can, J. Microbiol. II1 9(4-966. 1971. >. LIU, C., D. W. VOTH. P. RODINA. L. R. SHAUP and G. GONZALEZ. A comparative study of tb* pathogenesis of we*tern equine and eaetern equlae encephalomyelitl* viral Infection In mice by Intra cerebral and aubcutanaou* Inoculation. J. infect, Die. fill 61-19. 1970. I. MeLINTOCK. J., A. N. BURTON and 4. G. RRMPEL. Interepldemic hoata of waotorn encephalitis virua in Saskatchewan. Proe. of tho 64tb annual moating of the Now Joreoy Moequlto Extermination Aee. March. 1967. !. MIMS. C. A. Invasion of brain by yallow favor virua prevent in blood of mice. Dr. 4. oxp. Path, lit 129-886. 2867. 1. NIR. Y.. A. BEBMBR and R. A. G0LDWABS8R. Waat Nile virus Infection In mica following tvpneure to viral aaroool. Br, 4. oxp. Path. 4li 448-449. 1916. I. SABIN, A. B. Progression of different instilled virueee along different nervou* pathways In th* same host. Proe. 80*. exp. Biol. Mod. lit 210-911. 1911. i. SABIN, A. B. and P. X. OLITBKY, Variation in pathway* br which aqulno oncaphalomyalltia virua** invade CNS cf mica and gulnta pig*. Proe. Soe. axp. Biol. Ill 696497. 1988. . 8MORODINSTBPP. A.A. The aprlng-iummtr tickborn* aneaphalitt*. Areh. geo. Vlruafonch, 1: 494 480. 1949. BULKIN. S. B. Th* hat as a raaarvoir of virua** in nature. Prog. med. Virol. 4t llf.fOT. 1062. 1. SULKIN. S. B,, R. ALLBN and R. A. SIMS. Llpotroplem In pathogonaala of oneophalltls vtniaa* In Insoettvorou* hat*. Virology 11: 802-801. 1990. >. SYVRRTON. J. T. and G. P. BERRY. Susceptibility of th* gophar Cltellos rlchardaanli (Sabina) to Suing enephatomyolltla. Proe. Soe. oxp. BloL Mod. d. 841 888-814. 1980. WBBB, H. E. Reapone* to vinit infection* of th* central norvju* eratern and thtir consequent**. In Realetene* to Infoetioua Die**tee. R H. Dunlop and H. W. Moon. Editor*, pp. 298-271. Saskatoon > Modern Prana. 1970. . YUJLL. T. M. Viral and parueitle Infoetions of a population of anowahoo harm In Alberta. Theale, University of Wlaeonain. 1964. Velum* 42 -- April, 1978 MQNS 000851 191 axtnlques de cett* experience, comperellvement ux. porcelete conventionnela d'expt* rlancaa anWrleuree. Caa differences aersient tUribusblet k I'abaence da flora baelirianna inlesllnele, cKaa lea porcelete ax^niquea, at/ou k un ddveloppement molndra das systbmes cnsymetique* da detoxication du foie, chas lea Jeunea pores. it was considered important to determine the nature and site of PCB action in germfree pigs. In this study the clinical re sponse, pathological lesions and tissue levels of germfree pigs fed PCB was in vestigated and compared to similar previous observations in conventional pigs. INTRODUCTION MATERIALS AND METHODS Polychlorinated biphenyls (PCB) have been widely used in the organic chemical industry as plasticisers in paints, resins and plastics and in industry in heat transfer units and insulators. They have become among the most widely distributed and persistent pollutants of the ecosystem and have been detected in various forma of animal life (7, 28, 19, 21, 22, 23). Poly chlorinated biphenyls have been found to be present in agricultural products (18, 15, 16, 32) and in human tissues and blood samples (6, 21, 22). In animals they tend to accumulate in fatty tissues and in tis sues and organs rich in fat. Pathological lesions duo to PCB have been found in various organs of mAmmals but most se verely affected is the liver (10, 17, 20, 26, 35). In birds the cardiovascular system is damaged most severely, hydropericardium and edema being the most prominent lesions (XI, 12, 25, 30, 35). Lethal effects have been reported in chicken (11, 12, 25, 80) and in mink (6, 26, 31). Reproductive disorders due to PCB have been recorded in various species of animals (6, 10, 20, 24, 26, 27, SI). Previous work with conventionally reared pigs indicates that they tolerate relatively high doses of PCB without show ing clinical signa of toxicosis or grossly detectable pathological lesions, even though they may contain high levels of the chem ical in their tissues (28, 29). Concern has been expressed that such animals may pass packing plant Inspection aa fit for human consumption (29). It would there fore be of value to find a model similar but more sensitive to PCB than the con ventional pig. Due to the above considera tion and because there are indications that the presence of microbes may modify the reaction of animals to PCB (9, 14), Eleven colostrum deprived germfree Yorkshire pigiets were used for the ex periment. They were derived by hysterec tomy, reared in sterile isolators and mon itored for microbial contaminants accord ing to methods described previously (2). Beginning at fourteen days of age, eight of the pigs, two animats per group, were fed daily 12.6, 26, 60 and 100 mg/kg body weight respectively of PCB as Aroclor 1264 in olive oil added to the morning meal. It was dispersed in sterile condensed cow's milk by means of Tween 60. Three control pigs were fed a similar diet containing no Aroclor. AH animals were observed for clinical signs of intoxication and after death their organs and tissues were ex amined for gross and histopathological lesions and for PCB content. Necropsies were performed on principals when they died or when they were killed while mori bund. During necropsy the animals and select ed organs were weighed and the values obtained were used for calculation of the weight of each organ expressed as a per centage of total body weight. Small pieces of the organs and tissues were fixed in neutral buffered formalin and routinely processed to paraffin in a histokinette. Sections were cut at five microns and stained with H&E and PAS stains. Sam ples of various tissues were removed for PCB analysis and stored at -20*C until analysed. Polychlorinated biphenyls were extracted from tissues using the FDA multipesticide residue method (8). Com pounds were detected by means of a MicroTeck, Model 220', gas-liquid chromato graph, equipped with a "Ni high temper ature electron capture detector. The quanti- Traear Im., Alfa,la, Tmm. Mnffttranka Ltd., Shannan. Iralaid, Volum* 42 -- April, 1978 MQNS 000852 193 tation of PCB was performed by measuring total peak area as the detector response* using Infotronics Model 208* automatic digital integrator equipped with a base line tracking and drift corrector. Clinical Signs The principal clinical signs of PCB toxocosis were inappetance. erythema of the nose and the anus, diarrhea, distended abdomen and retarded growth and at dose levels higher than 26 mg/kg incoordination and coma followed by death within three weeks after exposure. Regardless of the dosage level, the treated pigs had reduced appetites begin ning from five to seven days after ex posure to the chemical. The pigs fed Aroclor 1254 at the 12.6 mg/kg level re gained their appetites about three weeks after exposure while the appetites of the pigs fed the higher levels became pro gressively poorer until prior to death they had a complete anorexia. The onset of diarrhea in the pigs fed 100 and 60 mg of Aroclor per kg body weight was first observed nine to eleven days after exposure and in those fed 26 and 12.5 mg/kg on day 19. Feces of the pigs fed the lower levels remained liquid and light brown to dark brown in color until termination of the experiment, while in those fed the higher levels the facet changed to black and tarry and in extreme cases contained visible blood. The ani be came inflamed and one pig fed 12.6 mg/kg had a prolapse of the rectum. The abdomena of all the treated animals became distended. Those pigs fed Aroclor 1264 at 100, 50 and 25 mg/kg levels were ^coordinated, progressed to semlcomatose or comatose state and either died or were killed in extremis. The deaths of pigs be longing to the respective groups occurred on day 11 (100 mg/kg), days 20 and 21 (60 mg/kg) and days 32 and 40 (25 mg/kg) after exposure to the chemical. Of the animals fed 12 mg/kg, the pig that had prolapsus recti was in a semlcomatose state on day 36, when it was killed and necrop- sied. The other pig of this group remained in a relatively good state of health until it was killed on day 40 after exposure or st 63 days of age. Microbiological examination of samples collected at weekly intervals and at necrop sy indicated that the animals had been bacteriologically sterile throughout the ex periment. The growth ratea of the pigs exposed to Aroclor 1264 were reduced as compared to the normal growth curve of germfree pige fed similar diets without the chemical (Fig. 1). The three control pigs remained healthy. One of them was killed at 34 days of age and the other two were killed at 63 days of age. Necropsy and Histopathological Observations Weighte of treated pige et time of death Numbers (100,90,29.12.9)-deily dote of Aroelor (mg/kg) n11*1.4, 1u. Wc*Bil|ihrtehMImUm* wi*rltahUtiMf *Mlrat UMra cAanntratMU. At necropsy the principals were ob served to be small in size for their age with long hair, emaciated and dehydrated to varying degrees. Lesions were seen in the liver and in the cardiovascular, digestive, immunological and certain elements of the endocrine systems. In all of the animals the most obvious lesion was a hypertrophied mottled liver. The degree of hypertrophy of both the livers and kidneys increased in relation to the levels of Aroclor in the diet. All pigs, regardless of the dosage level had micro scopic lesions of hepatic centrolobular ne crosis of varying severity (Fig. 2). One pig in each of the treated groups had a serosanginous fluid in the peritoneal cavity and hemorrhages through the serosa of the mesentery and Intestinal wall. A pig 194 Con. J. comp. Mod. MONS 000853 Pit. I. Ctntrolabilar amniIi In liTr *r tormrm pt| M 110 m/ki el PCB. Net* the poaition ! tw* atrrotk facl iltcKOr aff *kr In tha lira? tobak. HAS. KOO. which had received PCB at a dose level of 50 mg/kg had fibrinous pericarditis (Fig. 3) and a slight interstitial myocardi tis. Interstitial myocarditis (Fig. 4) along with endocardial thickening was seen in another pig fed PCB at the level of 100 mg/kg. Five of the PCB fed pigs had slight microscopic lesions of myopathy in the psoas and gastrocnemius muscles (Fig. 6). The stomachs of the pigs fed 100 and 50 mg/kg of Aroclor contained excessive mucus and one pig that was given the higher dosage level had large areas of ero sion of the mucosa and hemorrhages along the greater curvature. All exposed pigs had colitis regardless of the dose of PCB administered. The walls of the caecum and of the colon were thickened and the mucosa was congested. The contents of the large intestines of the pigs receiving 100 and 60 mg/kg of Aroclor were black in colour and positive for occult blood. These animals had microscopic lesions in the stomach and in the colon, consisting of moderate infil tration of the gastric mucosa with inflam matory cells and excessive secretion of mucus and lesions of late colitis (Fig. 6). All of the treated animals had grossly observable swollen and congested thyroids and one of the pigs fed Aroclor at the 12.5 mg/kg level appeared to have a swell- Voluim 42 -- April, 1978 Pl*. 4. Kr*rAI(a In prnfrM lf M l *rAt PCB. Nat* dtamk feeI of InflamwaUrr call* (arrow*). Has. SM. 195 MOWS 000854 TABLE I. Relative Weights of Internal Organs of Germfree Pigs Fed Aroclor 1254* . Organ Dally Dose of Aroclor (mg/kg body weight) Neg. Conctr. 12^5 JTo 50 100^ Organ Weight -- Eipressed as % of body weight Liver........................................ Kidneys................................... Testicles................................... Spleen...................................... Thymus................................... 2.9 0.52 0.14 0.16 Normal 7.51 0.62 0.09 0.16 Reduced 8.81 0.98 0.11 0.11 Much red. 10.43 1.17 0.08 0.06 Absent 12.60 1.18 0.08 0.11 Absent The recorded values represent arithmetical means from two pigs of each of the treated groups ing of the adrenals. The thymus was hypo plastic and in those pigs fed Aroclor for the longest period of time at the lower levels both the thymus and body fat ap peared to be absent. The apleen and the testicles of the treated pigs were reduced in size and weight as compared to those of the control pigs. The weights of select* ed organs of the nontreated controls and the treated pigs expressed as a percentage of the total body weight are presented in Table I. No lesions were observed in the organs and tissues of the control pigs and no significant histological lesions were seen in the lungs, kidneys, spleens, adre nals, thyroid and thymus glands of the treated animate. Tissue Distribution of PCB have been observed only following adminis tration of high doses of PCB or after prolonged exposure. Feeding PCB to ma ture sows has resulted in reduced fertility and chronic septicemia with liver hyper trophy and gastric erosions (10). There is also evidence that PCB interfere with the reproductive function of the male pig (27, 29). In growing conventional pigs, low doseB of PCB stimulate growth, while high doses suppress the growth rates (28, 29). Multiple, but generally mild histological lesiuns due to PCB have been observed by the cited authors in conventional pigs of all ages. These include hepatitis, focal hepatic necrosis and cirrhosis, acute in terstitial nephritis and nephrosis, erosions of the gastric mucosa, degeneration of the skeletal muscle and myocardium and The concentrations of PCB in tissues of the treated animals are shown in Table II. The highest concentrations of PCB occurred in the adipose tissues of pigs given 60 mg/kg and 100 mg/kg. Piglets fed 12.6 mg/kg and 25 mg/kg of PCB were emaciated to the point that adipose tissues were not available for analysis. The hepatic levels were next to adipose tissues in concentrations but were substantially lower than the former. Brain concentra tions were consistently lower than those in |`ver and muscle. The levels were also high In testicles. The ratios of brain versus blood concentrations were nearly identical in all animal analysis and varying from 4.1 to 4.6. DISCUSSION In conventional pigs, clinical signs of Mcretle. iM fiw ( kin cantrallr IftoS uikl toxicosis and gross pathological lesions (rrow). HAS. >4N. 196 Con. J. comp. Mod. HONS 000855 TABLE II. Concentrations (in nA/g wet tissue) of PolychlorlnatecTBtbhenyla In Various Ttssuss of Germfree Pidled Given Daily Graded Doses of Aroclor 1254* Dose Level Tissue 12.5 mg/kg 25 mg/kg 50 mg/kg Brain.................................... ........... Heart................................... ............. Kidney................................. ............. Liver.................................... ............. Lunj..................................... ............. Psoas muscle........................ ............. Testicle................................ ............. Bile....................................... ............. Fat....................................... Blood.................................... ............. 8.0 3.2 6.9 9.6 5.3 15.3 5.3 5.3 1.77 11.7 34.0 17.2 24.8 6.8 20.8 40.0 65.9 7.1 26.5 163 64.4 8.6 27.3 --65,7 75.1 1864.0 -- 8.2 The recorded values represent arithmetic means from two pigs 1M mg/kg 101.7 202.5 54.3 101.6 2315.5 12,5 lesions in the brain. The described lesions have not been consistent but one or more have been observed in some of the exposed animals, the liver lesions being present most consistently. In germfree pigs, clinical manifestations of toxicosis appeared earlier, the growth was suppressed more severely and the in cidence of fatalities was higher and they occurred after a shorter period of exposure than has been observed in conventional pigs. Abdominal distention and signs of intestinal irritation as seen in the gnotobiotic pig have not been reported in the conventional animal. The degree of liver hypertrophy of the germfree pig greatly exceeded that of con ventional pigs (Table I). Unlike the con ventional pig but similar to poultry (11, 12) some of the germfree pigs had a hydropericardium and ascites and like mink (5, 20, 31) they had black tarry feces and hemorrhages in the gastrointestinal tract and in the abdominal cavity. Hyper plasia and dysplasia of the gastric mucosa, even though observed in a mild form in the conventional pig, were more pronoun ced in the germfree pig. Lesions resem bling these have been observed in primates fed PCB (3, 4). The hypoplastic thymus observed in most of the PCB fed germfree pigs, similar to that reported in the rabbit (33, 34), indicates an immunosuppressive effect of Aroclor 1254 in the pig. There are reports that PCBs have an unfavourable effect upon the reproductive function in several species of animals in cluding swine (10, 27, 29), mink (5, 26, 81) and poultry (24). While no direct assess ment of the reproductive capacity of the germfree pigs could be made in this study because these animals did not reach a suffi cient age, the reduction in the size and weight of the testicles of the male germ free pigs exposed to PCB as compared to those of the negative controls would sug gest a deleterious effect of PCB upon the reproductive organs. As compared to conventional pigs, germ free pigs appear to accumulate higher levels of PCB residues in their tissues. For example, the following residue levels were observed In conventional pigs fed 16 reg/kg body weight daily for six weeks (29) and in germfree pigs fed 12.5 mg/kg daily for five and seven weeks (Table I). Volume 42 -- April, 1978 HONS 000856 197 brain. liver............. psoas muscle. Conventional pig* 6.6 ppm 122.9 ppm 7.8 ppm 4.9 ppm Cwmfroo plfi (moan) o- ppm insufficient sample 9.6 ppm 153 ppm In the same two experiments the con* ventional pigs consumed over a 12 week period a total of 860 mg/kg of Aroclor 1264 and germfree pigs fed 50 mg/'kg of body weight during 20 days consumed 1000 mg/kg body weight of the PCB. Here the respective tissue levels were as follows: brain.................. fat........................ liver..................... psoas muscle....... Convntlonal pigs_______ 8.8 ppm 226.2 ppm 5.9 ppm 5.9 ppm Germfree pigs 34 pmm 1864 ppm 65.9 ppm 64.6 ppm These differences, oven though arrived at in experiments that are not directly comparable, would suggest a more effi cient absorption or retention of PCB by the germfree pig. The results of the present study thus indicate that the germfree piglet is fatally affected by doses of PCB which are either of no or only minor clinical and gross pathological consequence In somewhat older pigs maintained under conventional conditions. The response of the germfree pig is in many respects similar to that of its conventional counterpart but it is more severe. In addition germfree piglets display lesions that have not been observed in conventional pigs but have been seen in a variety of other species exposed to PCB, including primates. When graded doees of PCB were administered to germfree pigs, correlation could be made between clinical signs, gross and histopathologlcal lesions and residue levels of PCB in the tissues. As concentration of PCB in blood increased with the dose administered, and as the brain levels increased correspondingly, the ratios of brain versus blood concentrations may be indicative of PCB transfer across the blood-brain barrier in the germfree pig. The greater susceptibility to PCB of the germfree pigs used in this study as compared to conventional pigs was prob ably related to the absence of bacteria In the digestive tract of the germfree pigs and to their younger age. The observation that hydroxy metabo lites of PCB have been identified in bac teria in tin vitro studies suggests that also in vivo part of the ingested PCB may be metabolised by the intestinal bacterial flora. Germfree pigs, having no such flors, would therefore have available for abeorption a greater proportion of the ingested chemical than would the conventional animal. Our findings that germfree pigs actually had higher PCB residues In their tiseuos than those detected in conventional pigs fed approximately equal quantities of PCB per unit body weight would support this assumption. Being younger than the conventional pigs that have been investi gated, the germfree pigs likely possessed less developed detoxifying enzyme systems in their livers than did the conventions! pigs and therefore probably would be af fected more severely by the toxic effects of PCB even if the quantities absorbed were equal. On the basis of this work it appears that germfree pigs where the effects of PCB are not masked by the presence of environ mental and intestinal microbes could prov ide a sensitive and useful tool for the study of PCB toxicosis even in relatively low concentrations. Studies of PCB in gnotobiotlc animals associated with a defined flora may further elucidate the role of specific microbial organisms in the absorption end retention of PCB by higher animals. ACKNOWLEDGMENTS The authors would like to express their appreciation for technical assistance to Mr. D. Jo!, Mrs. P. Lehman, Mrs. G. Hodson, 198 Con. J. comp. Med. HONS 000857 Mr*. T. Kuipers and Mr. P.J. Ruhnke. The financial assistance of the Ontario Depart* ment of Agriculture and Food and the Canadian Medical Research Council (Grant MA'2082) is gratefully acknowledged. RBFERBNCBS 1. ACHM1D. M. and O. D. POCHT. Oxidation of polyoblorlneted biphenyl* by Achromobacter rCB. Bull, onvlr. Contain. Toxic. 8: 70-72, 17S. 2. ALBXANDBR. T. J-, O. P. MINIATB. 0. G. IN GRAM. R. C. THOMSON and I. L. THACKERAY. Onotoblotie pit* i procurement, microbial flora, serum protolnt and lymphatic tlaauaa. Can vat. i. lOt 99-106. 1989. I. ALLBN. J. R. and D. H. NORBACR. 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J. fl. Toxicology of PCBe for mammal* and for blrde. Bnvlr. Hlth Proep. 1: 109-117. 1979. Velum* 42 -- April, 1978 MONS 000858 199 San Miguel Sea Lion Virus Fed to Mink and Pigs F. W. Wilder and A. H. Dardiri* ABSTRACT Mink became infected with San Miguel ea lion virus when fed ground meat from seal carcaeeee showing resicular-llke lesions in the skin. The mink also contracted the in fection when they were fed San Miguel sea lion virus Infected pig meat or cell culture propagated virus. San Miguel sea lion virus infection in mink was Inapparent but the virus was isolated from blood and rectal swabs. Pigs treated similarly with the same virus preparations given to mink developed a severe vesicular disease syndrome similar to that produced by vesicular exanthema of swine. In n separate trial, piga fed a large sample of commercial ground seal most did not develop disease signs er antibodies. Fur ther work is needed to assess the hasard of introducing San Migual aea Hon viroe into swlno on the same premises when potentially Sen Mlgutl sea lion virus Infective seat meat is fed to mink. RfiSUMfi Le fait d'alimenter dss vieons avec do ia viande hechle provenant do carcasses d'otariss i fourrurs qul prdsentaient des lesions ententes rssssmblant h des vtsiculeo, fit rtaUser qu'oa les infeetait avec le virus de I'otarie de San MigueL Los visons contract*rent aussi 1'infection apr*e avoir absorb* do la viande de pore ou dee cultures tieeuluiree qui contenaient ce virus. L'lafeetiea passu (nepercue, mala on isola lo virus * partlr du sang et d'leouvillons du rectum do cos visons. L'utitistlon de pores su lieu do visons, dsns uno exptrience similsire, se traduisit par I'apparltion d'un syndrome vtclcutaire greve et tern- Plow Ulead Animal DInih Castor, AsrlcalUral ItMarch Sarrtea. U.B. ZtosertSMRl f Afrieeltera. Grwnpart, Nav Yark 11044. Maatton at a tra4amark #r prasriaUrv freSatt On nat canatiteto a faarantoa or warrant? at tha #ra4el kr iM U.S. Dapartmani *1 Aertoeltara a4 4aaa nat Implr Ito approval to Ika aialealen at athar pra4acta that map alaa ha aaltabia. Sabmltto4 Map ia. 1ITT. btnble * celui que provoque I'exenthtme v*elculsiro du pore. Au coore d'une autre exp*risnee, les pores qui avslent mang* on tehantillon commercial consldtrable de viande hach*e d'oterle i fourrure ne d*velopp*rent pee de signes de maledie, ni d'snticorps. II feudrs effeetuer d'sutres expdriences afin de prdciser le danger d'lntroduire le virus de I'otarie de San Miguei ches des pores qui vivent sur la mime ferme que des visons suxqusla on donne do le viande d'otarle * fourrure qui pourrait receler ce viros. INTRODUCTION San Miguel sea lion virus type 5 (SMSV5) has been isolated from a vesicle on a skin sample obtained from the northern fur seal (Callorhinus ursinus) found on the Pribilof Islands in the Bering Sea (3). Observers of the annual culling of three and four year old bachelor males from the rookeries on the Pribilof Islands noticed that certain seals had ruptured vesicle like lesions on the skin of their flippers. San Miguel sea lion virus was isolated from meat ground from seals with skin lesions after the seals had been skinned and evisaerated (John C. Sawyer, personal commu nication). Large amounts of seal meat are a by-product of the annual culling. Ground seal meat is then shipped to the U.S. main land as mink feed. Some mink ranchers keep pigs to feed on the ground seal meat that drops under the mink cages. Thus, feeding seal meat to both mink and pigs may represent a potential danger to the swine industry because SMSV is indistin guishable physiochemically and morphologi cally from vesicular exanthema of swine virus (VESV) (2). Furthermore, SMSV and VESV produce similar vesicular di sease features in pigs. The purpose of this study was to determine whether mink or pigs would become infected by feeding on seal meat infected with SMSV. 200 Can. J. comp. Mad. MONS 000859